The high prevalence and above average severity of obesity in African Americans is of major public health and clinical concern. The overall objective of the proposed studies is to generate critically needed insights about ways to improve the effectiveness of lifestyle behavior weight loss programs in African Americans, particularly women, for whom levels of clinically significant obesity far exceed those in African American men or white women or men. Intervention study designs can be enhanced by reference to empirical information about factors found to be associated with the best weight outcomes in African Americans exposed to various treatment approaches. The approach takes advantage of data sets from three clinical trials and a community program evaluation, conducted by the same research group and using the same core principles of behavioral counseling. Proposed analysis will expand upon published main results of the separate studies and focus particularly on pooled analyses across studies. The randomized clinical trials had 11 to 24 months (depending on the study and on participant enrollment date) of treatment and follow up. The community program evaluation study had 10 to 20 weeks (depending on program delivery site and participant choice) of treatment. Together, the four studies enrolled nearly 900 African Americans (~90% women). There are major advantages to pooling data across these studies, including increased sample sizes overall;increased sample sizes for subgroups of interest, e.g., based on gender, education, age, marital status, health status, or initial level of obesity;variation in patterns of treatment offered and in drop out and attendance at treatment sessions;increased range of weight change for both initial and longer term follow up;and ability to compare weight outcomes in different settings (research clinic, primary care practices, and community organizations). Specific aims are to: 1) characterize study participants according to participation patterns and levels, and patterns of initial weight change outcomes;2) characterize participants who are able to achieve and maintain clinically significant weight loss;3) characterize participants with the largest improvements in clinical or psychosocial outcomes such as waist circumference, blood pressure and QoL;and 4) compare weight change and QoL across different treatment settings and modalities. Potential independent variables available in two or more of these data sets reflect motivation, self efficacy, stress, life events, quality of life, social support from family and friends, neighborhood context variables, participation patterns (of interest as both predictors and outcomes), and adherence to behavioral change recommendations. Findings will yield at least four scientific articles describing success factors and addressing potential ways to improve retention, attendance and weight loss outcomes in African Americans who enroll in weight loss programs. PUBLIC HEALTH RELEVANCE: African Americans, particularly women, are at high risk from obesity and related complications, but evidence from efficacy trials indicates that standard obesity treatment approaches are less effective in African Americans than in whites. To inform the design and implementation of more effective programs, the proposed secondary analysis of data from 3 clinical trials and one community-based program conducted by our research group within the last decade will provide new insights into variables related to success in weight loss programs.